This project pertains to the spotted fever problem in the United States and includes studies related to the ecology, identification, and characterization of Rickettsia rickettsii, and of closely related hitherto undescribed tick-borne rickettsiae in this country. Direction and scientific support are provided to outside agencies (state health departments, public health laboratories, hospitals, physicans, etc.) in establishing educational programs about ticks and tick-borne diseases, in conducting tick/rickettsial surveys, and in training personnel in recently developed diagnostic procedures. This project also deals with the cellular and subcellular interaction of tick-borne agents, particularly rickettsiae, and their vectors. BIBLIOGRAPHIC REFERENCES: Krinsky, W.L. and Burgdorfer, W.: Trypanosomes in Amblyomma americanum from Oklahoma. J. Parasitol. 62: 824-825, 1976. Krinsky, W.L.: Nosema parkeri sp. n., a microsporidian from the argasid tick, Ornithodoros parkeri Cooley. J. Protozool. 24: 52-56, 1977.